Turbocharger

ABSTRACT

A turbocharger may include a shaft having a central hole longitudinally formed therein, a supply hole for supplying oil to the central hole, and an exhaust hole for discharging the oil from the central hole to the outside of the shaft. The turbocharger may also include a turbine disposed at a side of the shaft and rotated by an exhaust gas, a compressor disposed at the other side of the shaft and compressing intake air, a bearing rotatably supporting the shaft, and a center housing mounted with the bearing.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority of Korean Patent Application Number 10-2013-0113910 filed Sep. 25, 2013, the entire contents of which application is incorporated herein for all purposes by this reference.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention relates to a turbocharger in which a turbine is rotated by an exhaust gas, a compressor operated by the turbine increases the power of an engine by compressing intake air, and the quality of the exhaust gas is improved.

2. Description of Related Art

Turbochargers have been generally used for internal combustion engines, particularly, for the engine of heavy trucks or ships. Recently, those turbochargers are used for vehicles in order to achieve large power from small engines. Further, the turbochargers improve the quality of an exhaust gas by making fuel more completely burn. General function and design of the turbochargers are known in the art.

The turbochargers include a turbine rotated by an exhaust gas and a compressor operated to compress intake air by the turbine, in which the turbine and the compressor are connected by a shaft. On the other hand, rotation reaction delay time (turbo lag) of the turbine, the shaft, and the compressor is generated in the turbochargers and studies for reducing the turbo lag have been conducted. Further, studies for effectively lubricating and cooling the periphery of the shaft while the shaft rotates at a high speed have been conducted.

The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

SUMMARY OF INVENTION

The present invention has been made in an effort to provide a turbocharger having advantages of having improved durability and performance by cooling and lubricating a shaft, which is equipped with a turbine and a compressor at both sides and rotates in a sensor housing, through a bearing.

Various aspects of the present invention provides a turbocharger including: a shaft having a central hole longitudinally formed therein, a supply hole for supplying oil to the central hole, and an exhaust hole for discharging the oil from the central hole to an outside of the shaft; a turbine disposed at a side of the shaft and rotated by an exhaust gas; a compressor disposed at the other side of the shaft and compressing intake air; a bearing rotatably supporting the shaft; and a center housing mounted with the bearing.

The supply hole and the exhaust hole may be disposed with a predetermined distance therebetween in a longitudinal direction of the shaft. The supply hole may be formed close to the compressor and the discharge hole may be formed close to the turbine. The supply hole and the exhaust hole each may be formed at a predetermined angle in the rotational direction of the shaft. The central hole may be formed in an area corresponding to the bearing. The oil may cool and lubricate the periphery of the bearing and the shaft while circulating an oil line formed in the center housing, the supply hole, the central hole, and the exhaust hole.

In accordance with various aspects of the present invention, by forming the shaft having the turbine and the compressor at both sides and disposed in the center housing to be rotatable by the bearing as a hollow shaft with a central hole, and by reducing rotational inertia moment, turbo lag can be reduced. Further, as the bearing and the shaft are lubricated and cooled by circulating oil through the central hole at the center of the shaft, the performance and the durability can be improved.

The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing a turbocharger.

FIG. 2 is a cross-sectional view showing an exemplary turbocharger according to the present invention.

FIG. 3 is a partial exploded cross-sectional view of an exemplary turbocharger according to the present invention.

FIG. 4 is a partial exploded perspective view of an exemplary turbocharger according to the present invention.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

FIG. 1 is a cross-sectional view showing a turbocharger. Referring to FIG. 1, a turbocharger includes a turbine housing 100, a center housing 110, a compressor housing 120, a compressor 130, a shaft 140, a turbine 150, and a bearing 160.

The turbine 150 is fitted on one end of the shaft 140 and the compressor 130 is fitted on the other end of the shaft 140. The bearing 160 is disposed on the shaft 140, between the compressor 130 and the turbine 150, and the shaft is disposed rotatably in the center housing 110 by the bearing 160.

The turbine housing 100 is combined with the center housing 110, covering the turbine 150, and the compressor housing 120 is combined with the center housing 110, covering the compressor 130. An exhaust gas supplied from an exhaust manifold to the turbine housing 100 rotates the turbine 150 and operates the compressor 130 through the shaft 140. The compressor 130 takes air inside and pumps it to an intake manifold.

FIG. 2 is a cross-sectional view showing a turbocharger according to various embodiments of the present invention. The configuration in FIG. 2 which is different from that in FIG. 1 is described in detail, while the detailed description of the same or similar configuration is not provided.

As shown in the figure, the shaft 140, which is a hollow type, has a central hole 200 inside, and a supply hole 210 for supplying oil to the central hole 200 and an exhaust hole 220 for discharging oil from the central hole 200 are formed in the shaft 140. Accordingly, the oil supplied into the center housing 110 circulates through the bearing 160, the supply hole 210, the central hole 200, and the exhaust hole 220. In various embodiments of the present invention, channels or oil lines are formed in the center housing 110 and the bearing 160.

As described above, the oil lubricates the bearing 160 and the shaft 140 and cools the periphery of them while circulating through the bearing 160, the supply hole 210, the central hole 200, and the exhaust hole 220, such that the entire durability and performance are improved. Further, since the central hole 200 is formed at the center of the shaft 140, the weight of the shaft 140 decreases, the rotational inertia moment reduces, and turbo lag reduces, such that reactivity of an engine can be improved.

FIG. 3 is a partial exploded cross-sectional view of the turbocharger according to various embodiments of the present invention. Referring to FIG. 3, the central hole 200 is longitudinally formed in the shaft 140, at the area corresponding to the bearing 160. In more detail, the central hole 200 is formed at a predetermined length through the shaft 140 from the end portion where the turbine 150 is fitted.

The exhaust hole 220 is formed toward the center of the central hole 200 from the outer circumference of the shaft 140, the supply hole 210 is formed to the compressor 130 from the central hole 200, and the exhaust hole 220 is formed at the end portion where the turbine 150 is fitted. Accordingly, the supply hole 210 and the exhaust hole 220 are formed with a predetermined gap or distance therebetween in the longitudinal direction of the shaft 140. Further, in many cases, the diameter of the shaft 140 is large at the portion corresponding to the central hole 200 and small at the portion where the central hole 200 is not formed.

FIG. 4 is a partial exploded perspective view of the turbocharger according to various embodiments of the present invention. Referring to FIG. 4, the supply hole 210 and the exhaust hole 220 are formed inward from the outer circumference of the shaft 140. The supply hole 210 is formed at a predetermined angle in the rotational direction of the shaft 140 and the exhaust hole 220 is formed at a predetermined angle in the rotational direction of the shaft 140.

In various embodiments of the present invention, the diameter of the central hole formed in the shaft 140 is 0.5 to 0.25 times the diameter of the shaft 140, the supply hole 210 and the exhaust hole 220 are formed in the area corresponding to the bearing 160, the inner diameter of the supply hole 210 and the exhaust hole 20 is 1 to 3 mm, and the number of each of the supply hole 210 and the exhaust hole 220 may be two or more.

For convenience in explanation and accurate definition in the appended claims, the terms “outer” or “inner”, “inside” or “outside”, and etc. are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. 

What is claimed is:
 1. A turbocharger comprising: a shaft having a central hole longitudinally formed therein, a supply hole for supplying oil to the central hole, and an exhaust hole for discharging the oil from the central hole to an outside of the shaft; a turbine disposed at a side of the shaft and rotated by an exhaust gas; a compressor disposed at the other side of the shaft and compressing intake air; a bearing rotatably supporting the shaft; and a center housing mounted with the bearing.
 2. The turbocharger of claim 1, wherein the supply hole and the exhaust hole are disposed with a predetermined distance therebetween in a longitudinal direction of the shaft.
 3. The turbocharger of claim 2, wherein the supply hole is formed close to the compressor and the discharge hole is formed close to the turbine.
 4. The turbocharger of claim 2, wherein the supply hole and the exhaust hole each is formed at a predetermined angle in a rotational direction of the shaft.
 5. The turbocharger of claim 2, wherein the central hole is formed in an area corresponding to the bearing.
 6. The turbocharger of claim 2, wherein the oil cools and lubricates a periphery of the bearing and the shaft while circulating an oil line formed in the center housing, the supply hole, the central hole, and the exhaust hole. 